1. Field of the Invention
The present invention relates to an electronic musical instrument and, more particularly, to an electronic musical instrument which can obtain a resonance effect, a change in tone color, and the like, which are approximate to those of an acoustic instrument.
2. Description of the Prior Art
In most acoustic instruments, resonance tones (sounds) are produced in addition to musical tones (musical sounds) produced according to a player's performance, and a deep aftersound unique to an instrument can be obtained. For example, in an acoustic pipe organ, air is supplied to a predetermined stop (a mechanism for supplying a predetermined pipe (or pipes) with air) in accordance with a key ON operation of a player, and the pipe produces a tone. In this case, the acoustic energy of the predetermined pipe causes several non-driven pipes to resonate, thus producing resonance tones. The resonating pipes and the way of resonance of these pipes depend on the pitch of a pipe to which air is supplied, an interval relationship (in the case of a chord performance), a key ON time, a tone volume, the structure and arrangement of the instrument, and the like. When the tone volume of an ON key tone is controlled upon operation of, e.g., a pedal after tone generation is started, resonance tones are changed. In other words, the frequency structures and levels of the resonance tones are changed.
In, e.g., a piano, when the sustain pedal is depressed, strings are released, and resonance tones are produced under the influence of an ON key tone.
As an electronic musical instrument which realizes the same effect as the acoustic instrument, a technique disclosed in Japanese Patent Application Laid-Open No. Sho 60-91393 is known.
Japanese Patent Application Laid-Open No. Sho 60-91393 discloses an electronic musical instrument which produces a plurality of resonance tones having predetermined pitches corresponding to a pitch designated by, e.g., a keyboard. Japanese Patent Application Laid-Open No. Sho 64-91192 discloses a musical tone signal generation apparatus which stores in advance wave data of mixed waves of musical tone and resonance tones (which have to be generated in accordance with the musical tone) in storage, thereby generating deep musical tone including resonance tones, and which appropriately selects resonance tone waveforms in accordance with touch data of a keyboard or operation data of a pedal, and produces mixed tones.
The electronic musical instrument disclosed in Japanese Patent Application Laid-Open No. Sho 60-91393 can only produce resonance tones having pitches corresponding to a designated pitch in addition to a musical tone having the designated pitch. Thus, this instrument cannot delicately change resonance tones according to the touch on the keyboard or the operation amount of the pedal, and a resonance effect or a change in tone color approximate to an acoustic instrument cannot be obtained.
The musical tone signal generation apparatus disclosed in Japanese Patent Application Laid-Open No. Sho 64-91192 appropriately selects wave data of resonance tones in accordance with initial touch data, and performs mixing control according to an original ON key tone waveform and a pedal operation. However, after tone generation is started, the levels of resonance tones can only be controlled a pedal operation. Thus, it is difficult to reproduce a complicated change in resonance tones over some frequencies or levels as in an actual pipe organ.